Laboratoire de Biologie du Développement

High-pressure hydrogen storage vessels type IV (HPV), made from carbon fiber-reinforced composites, are essential for hydrogen-powered applications due to their strength and light weight. However, they remain vulnerable to internal defects such as porosities, which can compromise structural integrity. While certification tolerates some porosity, excessive levels may lead to failure. This study aims to predict both the number of porosity and the porosity rate category (low vs. medium/high) using XTRACTIS (XTS), a general reasoning artificial intelligence system, capable of automatically inducing robust and intelligible predictive models. For porosity rate classification, XTS and Boosted Tree were unable to find a robust model, due to a lack of information and erroneous values of the variable to be predicted. To model the log10 of the number of porosities, XTS automatically selected 15 out of the available 58 manufacturing variables to build 56 fuzzy IF…THEN rules, achieving an RMSE of 7.94% and a correlation of 0.824 on an external test dataset. The interpretable rules reveal relationships between process parameters and porosity characteristics, thus facilitating the understanding of defect formation mechanisms. The analysis revealed that uniform and stable fiber tension improves compaction and reduces voids, while heterogeneous or insufficient tension increases porosity. Optimized mandrel speed and winding angle enhance fiber alignment and resin distribution. Precise control of winding layer volume and doctor blade angle prevents dry zones and resin-rich areas, reducing porosity risk. Furthermore, the results emphasize the importance of monitoring and tuning multiple interacting parameters simultaneously to ensure composite quality. These findings highlight the value of augmented fuzzy cognitive AI in uncovering interpretable, domain-relevant interactions, supporting quality control and process optimization in advanced composite manufacturing.

The importance of auxin in plant organ development, including root nodule formation, is well known. The spatiotemporal distribution pattern of auxin during nodule development has been illustrated using auxin reporter constructs. However, our understanding of how this pattern is established and maintained remains elusive. Here, we studied how the auxin gradient is associated with the spatiotemporal expression patterns of known auxin biosynthesis and transport genes at different stages of nodule development in Medicago (Medicago truncatula). In addition, we examined the Medicago PIN-FORMED10 (MtPIN10) expression pattern and polar positioning on the cell membrane during nodule primordium development to investigate auxin flux. RNA interference and the application of auxin biosynthesis inhibitors were used to demonstrate the importance of auxin biosynthesis and transport at the initial stages of nodulation. Our results show that upon rhizobium inoculation before the first cell divisions, a specific subset of Medicago YUCCA (MtYUC) and MtPIN genes, as well as Medicago LIKE AUXIN RESISTANT2 (MtLAX2), are expressed in the pericycle and contribute to the creation of an auxin maximum. Overall, we demonstrate that the dynamic spatiotemporal expression of both MtYUC and MtPIN genes results in specific auxin outputs during the different stages of nodule primordia and nodule meristem formation.

How robust three-dimension (3D) organ shape emerges during morphogenesis is a fundamental question in biology. Addressing this question requires a comprehensive quantification of organ geometry in 3D. To tackle these issues, we considered the sepal of Arabidopsis as a model. Using a unique pipeline allowing to recover 3D sepal morphology, we analysed fifteen mutants affected in different pathways. The results of a Principal Component Analysis reveal sepal curvature as an important parameter accounting for variations in sepal morphology within genotypes. Unexpectedly, despite genetic homogeneity of the wild-type plants and reproducible culture conditions, we found a significant level of variability in sepal morphology. Our data also show that sepal shape from wild-type plants is more robust (less variable) than sepal size, hinting to a possible selective pressure on shape parameters.

How robust three-dimension (3D) organ shape emerges during morphogenesis is a fundamental question in biology. Addressing this question requires a comprehensive quantification of organ geometry in 3D. To tackle these issues, we considered the sepal of Arabidopsis as a model. Using a unique pipeline allowing to recover 3D sepal morphology, we analysed fifteen mutants affected in different pathways. The results of a Principal Component Analysis reveal sepal curvature as an important parameter accounting for variations in sepal morphology within genotypes. Unexpectedly, despite genetic homogeneity of the wild-type plants and reproducible culture conditions, we found a significant level of variability in sepal morphology. Our data also show that sepal shape from wild-type plants is more robust (less variable) than sepal size, hinting to a possible selective pressure on shape parameters.

Motile cilia are critical structures that regulate early embryonic development and tissue homeostasis through synchronized ciliary motility. The formation of motile cilia is dependent on precisely controlled sequential processes including the generation, migration, and docking of centrioles/basal bodies as well as ciliary growth. Using the published proteomics data from various organisms, we identified proliferation-associated 2G4 as a novel regulator of ciliogenesis. Loss-of-function studies using Xenopus laevis as a model system reveal that Pa2G4 is essential for proper ciliogenesis and synchronized movement of cilia in multiciliated cells (MCCs) and the gastrocoel roof plate (GRP). Pa2G4 morphant MCCs exhibit defective basal body docking to the surface as a result of compromised Rac1 activity, apical actin network formation, and immature distal appendage generation. Interestingly, the regions that include the RNA-binding domain and the C-terminus of Pa2G4 are necessary for ciliogenesis in both MCCs and GRP cells. Our findings may provide insights into motile cilia-related genetic diseases such as Primary Ciliary Dyskinesia.

In 2021, for the first time, a legal framework organizing the care of children with a variation in genital development (VGD), sometimes referred to as “intersex children” or “children with differences in sex development” (DSD), was introduced in France (article L. 2131–6 of the Code of Public Health). It should be immediately apparent that the chosen term, “variation” rather than “anomalies” or “disorders” – which was previously used in the medical world – reflects a political will to renew both the way of thinking and the medical practices in this field. The aim of the new legal framework is to guarantee optimum care for children with VGD by requiring the systematic involvement of expert centers (to establish diagnoses and therapeutic proposals), providing the most comprehensive information possible to their families and seeking the minor's consent. Among the possible medical care options, the law explicitly mentions “therapeutic abstention,” reflecting a paradigm shift aimed at curbing the too-frequent recourse to treatments whose sole objective is the conformation of the genitalia. An order was subsequently issued on 15 November 2022 to provide the necessary details for the implementation of the changes introduced by the law.

L’objectif : cet article vise à vérifier si les sources des inégalités salariales entre les femmes et les hommes sur le marché du travail au Cameroun résultent de l’existence d’un plafond de verre et/ou d’un plancher collant. Conception/méthodologie/approche : la méthode retenue est celle des régressions quantiles complétées par la technique de décomposition quantile Résultats : Les résultats obtenus soutiennent l’existence d’un plancher collant et recusent celle d’un plafond de verre. Ils montrent que les inégalités hommes /femmes de salaires décroissent au fur et à mesure que l’on s’élève le long de la distribution des salaires. Au sommet de la distribution, l’écart salarial au détriment des femmes trouve principalement sa source dans les différences de caractéristiques individuelles observables, alors qu’au bas de la distribution, cet écart est davantage dû à des facteurs exogènes à ces caractéristiques observables. Originalité/valeur : Notre article met en évidence le fait que, sur le marché du travail au Cameroun, le niveau de discrimination au détriment des femmes est une fonction décroissante des quintiles salariaux. Ce qui est à la fois un résultat original et de prime abord paradoxal dans la mesure où on se serait attendu à ce que d’éventuelles discriminations soient plus prégnantes au niveaux des emplois les mieux rémunérés. Ainsi, les femmes du Cameroun devraient viser à concourir pour des emplois hautement rémunérés dans la mesure où elles y sont moins exposées au risque de discrimination.